Generally described, a fuel conditioning system for a heavy duty gas turbine provides a flow of fuel to a fuel nozzle at a substantially constant pressure. If, for example, a natural gas supply pressure is too high, the fuel conditioning system needs to reduce the pressure before the flow of fuel reaches the nozzle. Such a reduction in pressure, however, may cause ice and hydrate formation in the flow of fuel due to the Joule-Thompson effect as well as local low pressure created by certain types of pressure control valves. Hydrates in the flow of fuel may cause nozzle erosion, flashback, and other types of combustion issues. Moreover, ice buildup could make a conventional pressure control valve inoperable. Ice buildup and hydrates inside the fuel conditioning system thus may be detrimental to the operation of the gas turbine power plant as a whole.
Known methods for reducing ice and hydrate formation include using water bath heaters and the like upstream of the pressure reduction valve. Such water bath heaters may include a natural gas boiler to heat the water supply. The use of such a water bath heater may be effective in maintain the temperature of the flow of fuel, but the water bath heater may be relatively expensive to operate. Moreover, operation of the natural gas boiler may require an emissions permit.
There is thus a desire for an improved fuel conditioning system for a gas turbine engine. Preferably such a system may deliver a flow of fuel at a substantially constant pressure to the nozzle without the use of water bath heaters or other types of parasitic loads while preventing ice and hydrate formation therein.